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Koalas in trouble after Queensland's bushfires and heatwave, expert warns

Alice Roberts and Jacquie Mackay,
Friday December 7, 2018 - 08:49 EDT

Queensland's recent heatwave has not been good news for the state's koala population.
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Queensland's koalas have fallen victim to the recent heatwave and bushfires with wildlife rescuers reporting a spike in calls to help.

And one koala expert from CQUniversity believes the conditions could have major long-term impacts on animal numbers in the state.

Various places across Queensland recorded their highest November temperature on record with Mackay reaching 39.7 degrees Celsius, Proserpine 44.9C, Gladstone 38.6C and Yeppoon 42.2C.

Fauna Rescue Whitsundays Jacqui Webb said local wildlife carers at Dysart and Moranbah have had 11 calls to help distressed koalas within 48 hours earlier this week.

Normally the local service would receive one to two calls a month.

"Obviously the heat out there has been detrimental to the koalas â€¦ and most of these koalas, the girls are seeing them lower down in trees, in trees that aren't native trees and on the ground as well which is definitely signs of heat stress," Ms Webb said.

She said koalas that were rescued and suffering from heat stress had responded well to treatment but two that had been hit by vehicles were not so lucky.

"We think they have been wandering a bit more than usual because they are looking for good leaf," she said.

Heatwave one of the biggest threats

CQUniversity koala researcher Alistair Melzer said it could be years before the full impact is known.

"The situation is koala numbers will have gone down as a consequence of this, particularly where the winds were at their strongest and where those fires occurred there'll be significant loss of koala populations, if not local extinction," Dr Melzer said.

"The Clarke-Connors Rangers, the Eungella area was severely affected by fire and that's been a significant refuge for koalas in Queensland for a long time.

"We're concerned there could be come long-term impacts on the viability of Queensland's koala population, depending on how badly those animals were impacted and how badly the habitat was impacted there."

He said history had shown that koala populations struggled in these conditions.

Dr Melzer said koalas had adapted to heat extremes as a species, so populations would survive in areas where they were able to find sufficient water and habitat.

But he said the survival of individual koalas depended on the circumstances in which they found themselves at the time.

"One of the biggest threats to koalas is heatwave," he said.

"When we've got these very hot, dry conditions, the koalas need to try and avoid the heat, and two, they need to get as much water as they can but the foliage itself is compromised because of the hot dry winds."

Dr Melzer said in those conditions koalas would try to seek shelter at the base of a tree, in creek beds or in tree hollows.

"Inevitably once the temperatures reach a certain point, the koalas will become heat exhausted and once that happens they'll rapidly die," he said.

"That's exacerbated by fire â€” even if a koala survives a fire, the tree canopies are scorched by the fire then the animals will not have access to food or water as well, so they'll suffer then too."

Populations may struggle to recover

Dr Melzer said while temperatures and the bushfire situation had eased, the stress of these kinds of weather events could also cause disease in the animals.

He said grazing, land clearing and increasing coastal development had all impacted on koala habitat.

Dr Melzer said it was difficult to monitor numbers in regional Queensland because of how widespread they were and in places, occurred in small densities.

"I think it's likely that we won't really know what's happening with the populations until another couple of weather cycles.

"We going into an El Nino now, so periods of dry weather, unlikely to see much recovery in that koala population," he said.

"You might be expecting to look to the next La Nina, so a run of wet years, where recovery of the koala population is more likely to be apparent."